Long-range shooting is not just about having a good rifle and a competent person behind the trigger; it’s also about having a properly configured, high-quality scope.
If you’re new to long-range shooting or are a seasoned long-distance shooter looking for a refresher, it is essential to know how to adjust and operate your riflescope.
Basic Anatomy of the Scope
Before learning how to adjust a rifle scope, it is essential to know about the different parts and associated terminology.
The parts of a typical rifle scope are as follows:
- Illumination adjustment: This setting is only found on illuminated scopes. Use it to turn the illumination on or off and adjust the brightness setting.
- Magnification adjustment: A rotating ring allowing you to adjust your scope’s magnification. Not found on fixed-power scopes.
- Objective lens: The lens facing the target.
- Ocular lens: The lens you look through when aiming.
- Ocular housing: Colloquially referred to as the eyepiece, it houses the ocular lens. On most scopes, the housing (or part of it) rotates and serves as the scope’s focus adjustment.
- Scope body: The thinnest, cylindrical part of the scope.
- Scope rings: A pair of rings serving as the mounting interface between your rifle and your optic. The ring diameter must match that of your scope body.
- Turrets: A scope may feature up to 3 turrets: one for elevation adjustment, one for windage adjustment, and one for parallax adjustment.
After installing it on your rifle, learn how to adjust a rifle scope for your intended purposes.
Eyepiece Focus Adjustment
Focus adjustment is critical for accuracy. You should make sure to correctly focus your eyepiece before making any other kind of adjustments. An incorrectly focused scope will either give a blurry image or a blurry reticle.
Ensure your lenses are clean; changing your focus adjustment means nothing if your lenses are smudged with fingerprints.
Get in a comfortable shooting position and aim the scope at a light-colored, plain background, such as a white wall or a blue sky. Avoid busy or dark backdrops. The idea is to make the background contrast with your reticle.
Once you’re in position, ensure your aiming eye is within the optimal eye relief distance. For example, if your scope’s eye relief distance is 3.8” – 4.5” and your eye is 4 inches from the ocular lens, you are within optimal eye relief distance.
Adjust the eyepiece focus until the reticle is as crisp and sharp as possible. Close your aiming eye for a few seconds, then open it again. If the image and the reticle both immediately appear sharp and clear, your eyepiece focus is correctly adjusted. If not, make minute adjustments and repeat.
Windage and Elevation
The most basic adjustment you can make with your scope is changing your point of aim (POA).
Changing your scope’s POA involves using your scope’s windage and elevation turrets. Knowing how to use these turrets is critical every step of the way, from zeroing to adjustments on the field.
If your scope uses an MOA reticle, check how many MOA per adjustment click your scope produces. For example, “¼ MOA per click” means one click of your windage or elevation turret will move the point of aim by ¼ MOA. At 100 yards, it corresponds to 0.25”.
The same principles apply if your scope uses a milliradian (mil) reticle but with metric units instead of imperial. “0.1 mil per click” means one click of either turret will move the point of aim by 0.1 mil. At 100 meters, this corresponds to 1 cm.
Parallax Adjustment
Parallax is a phenomenon occurring when your reticle and your target are not on the same plane. Contrary to popular opinion, parallax has nothing to do with ocular focus; simply bringing your reticle into focus will not correct parallax errors.
If you wish to become a competent long-range shooter (300 yards and beyond), you must have a keen understanding of parallax and know how to correct it.
To correct scope parallax, follow these steps:
- Stabilize your rifle (shooting stand, table, bipod + monopod, etc.) as securely as possible to eliminate any wobbling.
- Set your parallax adjustment to the maximum setting (indicated by an infinity symbol).
- Aim at the target, then perform the bobblehead test; move your head slightly left and right, then up and down. Pay attention to how the reticle reacts. If it appears that the reticle is moving as you move your eye, you have parallax issues.Slowly adjust your parallax setting as you continue doing the “bobblehead test.” If the reticle no longer moves as you move your head, your parallax adjustment is correct for your current distance.
You can tell whether your parallax setting is too low or too high by checking how the reticle moves when performing the bobblehead test.
- If you move your head to the left and the reticle moves in the same direction (e.g., head moving left, reticle goes left), your parallax distance is too low.
- If you move your head to the left and the reticle moves in the other direction (e.g., head moving left, reticle goes right), your parallax distance is too high.
Magnification Adjustment
Your scope’s magnification adjustment comprises two essential factors: the magnification power (or zoom) and the focal plane.
Magnification power is self-explanatory; the setting number indicates how much the image is magnified compared to reality. (e.g., A 5x setting will make the image five times larger relative to the naked eye.)
The focal plane determines your reticle’s behavior relative to magnification. There are two types: First Focal Plane (FFP) and Second Focal Plane (SFP).
First Focal Plane
If you have an FFP scope, your reticle magnifies along with the image. This focal plane is most useful for static target shooting.
- Pros: On an FFP reticle, the MOA or mil distances between each hash mark remain accurate at all magnification levels.
- Cons: At very high magnification levels, your crosshairs may obscure the target.
Second Focal Plane
If you have an SFP scope, your reticle size remains the same at all magnifications. This focal plane is most useful in situations where target distance is variable, such as hunting.
- Pros: The image is sharper and easier to read at all magnification levels.
- Cons: Hash marks represent different distances relative to the magnification, which may make precise adjustments challenging. This issue encourages some shooters to use the maximum setting only for consistency, which can potentially cause more problems (difficulties focusing, magnification too high for a given range, etc.)
Master Your Scope to Dominate the Field
Although it is vital to use the most accurate rifle and ammunition you can afford when shooting at extended distances, your platform’s mechanical accuracy means very little if you don’t properly configure your scope.
Therefore, it is critical to understand every function your scope possesses. Spend the time you need to adjust your scope; it’s worth the effort! There is no greater satisfaction than seeing your bullets hit the targets at 300, 500, 800 yards, and beyond.
You can also check out:
Proper Way to Sight-In a Rifle Scope
Choosing the Right AR-15 Reticle
For more interesting topics on scopes, check out how prism scopes works on this recent article. Also, check out these effective rifle scopes at 500 yards which are worth investing your money in.